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<h1>Haptics</h1>

<p><!WA0><img alt="-----" src="http://www.ai.mit.edu/icons/lines/line-bluemarble.gif">

<p>The haptics group at the <!WA1><a href="http://www.ai.mit.edu/">MIT
Artificial Intelligence Lab</a> conducts research in a wide variety of
topics related to touch perception and feedback including the development
of devices to effect haptic stimulation and software to render the sensations
of touch.  The group is headed
by <!WA2><a href="http://www.ai.mit.edu/people/jks/jks.html">Dr. Kenneth
Salisbury</a>.
Another group headed up by Ken is the
<!WA3><a href="http://www.ai.mit.edu/projects/handarm-haptics/manipulation.html">Vision
and Touch Guided Manipulation</a> group. <p>

The people in the Haptics group are: <p>

<ul>
  <li> Brian Anthony
  <li> Donald Green
  <li> Craig Latimer
  <li> Akhil Madhani 
  <li> Thomas Massie
  <li> Derek Schulte
  <li> Nick Swarup (graduated)
  <li> Chris Tarr
  <li> Criag Zilles (graduated)
</ul>

<hr>

One of our first developments was the Phantom Haptic Interface (distributed by
<!WA4><a href="http://www.sensable.com/">SensAble Devices, Inc.</a>): <p>

<h2>Touching is Believing</h2>
<br>

<!WA5><IMG ALIGN=BOT SRC="http://www.ai.mit.edu/projects/handarm-haptics/haptic-finger.gif">


The PHANToM represents a new generation of computer input devices. More than
just another passive, 3D mouse, the PHANTom allows users to actually feel
virtual objects. Unlike buzzing tactile stimulators, the PHANToM actively
exerts an external force on the user's finger tip - creating the illusion of
interactions with solid virtual objects. Smoothe spheres, flat walls, sharp
corners, and even texture can be convincingly conveyed to the human haptic
sytem using the device. This is not a bulky exoskelatal device - one simply
inserts his or her finger tip into the PHANToM and interacts with the virtual
environment. <p>

<hr>

<h2>High Fidelity</h2>

The PHANToM contains 3 motors which control the x, y, and z forces exerted on
the user's finger tip. Mounted on each motor is an optical encoder to
determine the x, y, and z position of the user's finger tip. The torque from
the motors is transmitted through a proprietary cable transmission to a stiff,
light-weight linkage. At the end of this linkage is a passive, 3 degree of
freedom gimbal attached to a thimble. The passive gimbal allows the thimble to
rotate so that a user's finger tip may assume any comfortable orientation. The
user's finger tip can then be modelled as a point or frictionless sphere
within the virtual world. The device has low friction, low inertia, and no
unbalanced weight so movements through free virtual space are unimpeded. <p>

<hr>

<h2>Versatility</h2>

The PHANToM is best described as a universal force-reflecting interface. In
fact, a stylus can be substituted for the thimble. A user can then manipulate
the stylus to control the tip of a virtual pencil or paint brush. Users can
actually feel the tip of the stylus touch virtual surfaces. The PHANToM can be
used as a high precision force-reflecting master for teleoperation or as a 3
DOF input device for CAD. Artists can mold clay within the computer and
surgeons can practice procedures on virtual patients.<p>

<hr>

<address>special-effects@ai.mit.edu</address>
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